You're probably seeing FS, the initials of the coin's designer Felix Schlag. All 1988 nickels would have either a P, D, or S mint mark. Any that you find in change are worth only face value.
The last time the US used a double mint mark was 1893, on coins struck in Carson City.
The letter D is the mint mark so it can't both have a mint mark and not have a mint mark.Please see the related question for more information.
You have to inspect your coin carefully. If it has a P or D mint mark, it's made of copper-nickel, not silver and is only worth 25¢. If it has an S mint mark and a copper-colored edge it's a copper-nickel proof coin worth maybe $2 to $10 depending on its quality. If it's in a holder labelled "Prestige Proof", then it IS a 90% silver coin. These were made for collectors and sell for $3 to $12 depending on quality and which state is depicted.
a quarter
You have to inspect your coin carefully. If it has a P or D mint mark, it's made of copper-nickel, not silver and is only worth 25¢. If it has an S mint mark and a copper-colored edge it's a copper-nickel proof coin worth maybe $2 to $11 depending on its quality. If it's in a holder labelled "Prestige Proof", then it IS a silver coin, but it's not solid silver. U.S. silver coins have at least 10% copper in them. These were made for collectors and sell for $3 to $15 depending on quality and which state is depicted.
If the coin came from circulation it's worth face value only. All circulating half dollars minted since 1971 are made of copper-nickel. Regardless of any urban legends, they do NOT contain any silver. If it's uncirculated in MS60 condition it's worth about $3.50. By the way, the coin should have a "P" mint mark on it.
The German 1 Mark coins from that era were actually made of copper-nickel, and the highest collector's value would be around $4, if it's still in uncirculated condition.
9.0000
The value would depend on the condition and date of the coin.
100-700 usd
The value of a Jefferson nickel with a p mint mark will vary depending on the year and the condition of the coin itself. A person should have the coin appraised for an accurate value.
There's no E mint mark. You're seeing the letter F which is the initial of the coin's designer, James Earle Fraser. The mint mark, if there is one, is on the back of the coin.
July 25, 2009 The value of a circulated Jefferson war nickel is based mainly upon the value of the silver they contain which is $0.78 today. In uncirculated collector coins the values vary greatly with the year and mint mark. To establish an estimated value for an uncirculated Jefferson war nickel, the year and mint mark must be known.
It may be a little older but is very common, just face value.
All Indian Head (also called Buffalo) 5 cent coins have the letter F on them. It is the initial of the engraver. The letter F has no bearing on value. Value of coins is determined by condition, date, mint mark and rarity.
Without seeing the mark it is difficult to give an estimated value. The mint did not intentionally make a nickel with a mark above the head but sometimes damage to the dies will create a mark. I would suggest you take it to a coin dealer who can actually see what you have and perhaps can give you more information about it.
$2 to $9000 depending upon the mint mark and the condition of the coin.
The coin is still found in circulation and is face value